add floating mode to expand widget

Author: geospatialem

demos/expand-component/index.html

@@ -35,7 +35,7 @@
     </calcite-navigation>
     <arcgis-map item-id="05e015c5f0314db9a487a9b46cb37eca">
       <arcgis-home position="top-right"></arcgis-home>
-      <arcgis-expand id="expand-el" focus-trap-enabled="false" close-on-esc position="top-right">
+      <arcgis-expand id="expand-el" focus-trap-enabled="false" close-on-esc position="top-right" mode="floating">
         <arcgis-search id="search-el"></arcgis-search>
       </arcgis-expand>
     </arcgis-map>